[patio11]

You'll catch a bit of unease with that motivation from some quarters, for what it is worth, but I generally applaud people making microecon 101 work for them.

There are two main branches of Rails in use today: 2.3.x and 3.x . Many of the idioms involved in day to day coding are strikingly similar, but the internals are incompatible in many ways. As a workaday Rails programmer you'll typically spend 95% of your time working far away from the internals, so a solid background in MVP design and Ruby / object oriented programming gets you pretty far on both Rails 2 and 3. Their magic incantations for doing some things are different but they can be cheat sheeted or Googled at need.

In general, you would expect greenfield development to be on Rails 3 but a lot of the money in the ecosystem is still in Rails 2 apps.

[mhartl]

In this vein, there's actually still a Rails 2.3 version of the Rails Tutorial online:

http://railstutorial.org/book?version=2.3